An unsigned fullword, set by the exit, that contains the length of the text pointed to by the error buffer pointer. The maximum length is 255 bytes. If the exit specifies a larger value, the assembler uses 255.

The assembler uses this length to determine whether to issue an error message. If the length is greater than zero, the text in the error buffer is inserted into one of the messages ASMA700I to ASMA704C. The assembler selects which message to issue by checking the value of the error severity field.

The contents of the error buffer are ignored on CLOSE calls to the exit, unless the exit requests immediate termination. If immediate termination is requested, the assembler generates an ASMA940U message with the text provided by the exit; all remaining open exits are CLOSEd, but might not provide any additional message text.